Inscribed angle theorem visualised

First rotation: B -> A

Second rotation: move triangle outside

Flip first outside triangle

Translate copy of outside triangle

Point to three angles adding up to 180

Angle wedge markers

Highlight right-angle, radius and tangent line

Point to blue angle remaining constant

Highlight constant red-green wedge

Arrows pointing at red and green arcs

Show that red+green is also the angle at peak of triangle